Audio and Video Question

[Death_of_Chaos]

I wasn't completely sure exactly what I should post this under but Graphics Cards seemed most fitting so if it needs to be somewhere else, I apologize in advance.

I've been looking up some info about this for quite some time but can't seem to get really the answer I'm looking for anywhere. I have an R9 280X that I connect to my 4KTV which routes sound from there to my surround sound. Doing it this way gives me only stereo sound as an option but connecting my computer directly to the surround limits me to a 1080p picture so I got a DisplayPort to HDMI adapter. Now what I want to try and do is lead audio from the HDMI port and then the video from the DP -> HDMI adapter. That's where my problem starts. At first my computer wanted to treat both connections as if it's a separate and in the process of trying to fix that, I've ran into other problems. Any help to figure this out would be extremely appreciated! I'll leave info of the hardware I'm dealing with. Also, all my drivers and everything are up to date.

The television's model number is P502ui-B1E is on Firmware 1.3.15-UHD.
http/cdn.vizio.com/documents/downloads/hdtv/P502uiB1/UM_P502uiB1.pdf

The adapter I'm using is the CAC-1070 from Club3D. This is what I'm gonna be using to connect to my television. I updated the firmware for the adapter just last night to fix the 60hz issue with 4K on my television and it indeed worked.
http/www.club-3d.com/index.php/products/reader.en/product/displayport-12-to-hdmi-20-uhd-active-adapter.html

My graphics card is an ASUS DirectCU II Top R9 280X and I just installed the latest driver last night.
https/www.asus.com/us/Graphics-Cards/R9280XDC2T3GD5/

My surround sound is a Sony HT-SS370. As far as I'm aware, there's no kind of software update for that.
https/docs.sony.com/release/HTSS370_EN.pdf

Finally got it to at least show up now. When it's working, the sound system comes up but says it isn't plugged in? I'll add a screenshot.

 

[americanaudiophile]

You could connect your PC with an SPDIF digital audio connection if it has one on the mobo or soundcard to the surround sound.
If your TV won't pass the surround sound then you could have extracted the audio from the HDMI output with one of these
http/www.bhphotovideo.com/bnh/controller/home?O=&sku=1161303&gclid=CPbRlczUrMwCFQFkhgodLxwPbw&is=REG&ap=y&m=Y&c3api=1876%2C92051677682%2C&A=details&Q=
and connected it to your audio system with an optical cable.

 

[Death_of_Chaos]

You could connect your PC with an SPDIF digital audio connection if it has one on the mobo or soundcard to the surround sound.
If your TV won't pass the surround sound then you could have extracted the audio from the HDMI output with one of these
http/www.bhphotovideo.com/bnh/controller/home?O=&sku=1161303&gclid=CPbRlczUrMwCFQFkhgodLxwPbw&is=REG&ap=y&m=Y&c3api=1876%2C92051677682%2C&A=details&Q=
and connected it to your audio system with an optical cable.

Buying a $75 piece of hardware isn't an option. I've tried optical before and it doesn't work very well and when it does, I still get only stereo. I'd much rather solve this problem with what I already have and with the setup I'm trying to accomplish as described in my question. Thanks for the suggestion though.